1. Field of the Invention
The present disclosure relates to a bone anchoring device, and more particularly to a monoplanar bone anchoring device with a selectable pivot plane. The bone anchoring device comprises a receiving part for receiving a rod, an anchoring element having a first end for insertion into the bone or into a vertebra and a second end including a head, wherein the anchoring element is movable relative to the receiving part in a limited angular range about the longitudinal axis, the angular range lying in a single plane. The bone anchoring device further comprises a guiding member configured to rotate in the receiving part, wherein a form-fit connection between the guiding member and the anchoring element limits the movement of the anchoring element to the single plane and wherein the single plane can be selected by rotating the guiding member. The orientation of the pivot plane is fixed by a first locking element that acts onto the guiding member and the angular position of the bone anchoring element is locked by a second locking element that also fixes the rod.
2. Description of Related Art
U.S. Pat. No. 7,749,258 B2 describes a bone anchoring device including a receiving part for receiving a rod and an anchoring element being movable relative to the receiving part in a limited angular range about the longitudinal axis of the receiving part, wherein the angles are lying in a single plane.
U.S. Pat. No. 7,951,172 B2 describes a bone screw assembly including an anchor portion and a head portion, such as a rod-receiving portion, movably mounted to the anchor portion to allow for controlled angulation between the anchor portion and the head portion. The anchor portion is pivotable in one or more selected directions about an axis relative to the head portion. A restriction member prevents the anchor portion from pivoting in one or more different directions about another axis relative to the head portion and/or spinal fixation element received in the head portion. The restriction member may also serve as a compression member and/or rod seat for seating a spinal rod coupled to the bone screw assembly.
The bone anchoring devices described above all have one or more defined positions relative to the rod in which the shank can be pivoted in a single plane.
U.S. Pat. No. 7,766,944 B2 describes an anchoring element for fastening a rod of a device for adjusting a human vertebral column on a vertebra and having a retainer-receiving a rod, a securing element attachable on the retainer and acting against the rod, a fastening element for attachment to the vertebral body and a clamping device between the retainer and the fastening element including a ring-shaped mount, a partially spherical bearing and an intermediate element embedded in the mount and surrounding the bearing. The bearing comprises level guiding surfaces on opposite sides. The intermediate element has mating counter surfaces which enable the retainer to move in one axial direction only relative to the fastening element.